Self-lubricating, organic-silicone rubber material, its preparation, process and use

ABSTRACT

The present invention provides a self-lubricating organic-silicone rubber material and its preparation process. The self-lubricating organic-silicone rubber material comprises organic-silicone rubber, self-lubricating additive, filler and vulcanizing agent, and optionally, release agent and pigment. The self-lubricating organic-silicone rubber material of the present invention can be used in various glass-cleaning appliances, especially the screen wiper of vehicles.

TECHNICAL FIELD

The present invention relates to an organic-silicone rubber material, inparticular, it relates to a self-lubricating, organic-silicone rubbermaterial containing a self-lubricating solid additive. The presentinvention also relates to the preparation process of the silicone rubbermaterial and its use in, for example, the screen wiper of vehicles.

BACKGROUND

The screen wiper on the windshield of vehicles can clean the windshieldand improve the sight when driving in rain and/or snow. Traditionalscreen wipers are made from natural rubber, which is easy to age due toits poor weather resistance, and thereby the screen wiper can not wiperainwater and clean the windshield well. Besides, the screen wiper wouldjump and generate noise.

In order to solve the above problems, many attempts have been made. Forexample, various coatings are applied on the surface of the rubber toimprove the contact surface between rubber and glass, thereby enhancethe cleaning effect. Attempts also have been made to replace thetraditional rubber with silicone rubber because silicone rubber itselfpossesses excellent weather resistance and can prevent aging, but verystrong friction between silicone rubber and glass would occur, leadingto difficulty in the application.

TW 412487 discloses a silicon rubber screen wiper based on siliconerubber, to which a fluorine-containing compound and micro glass spheresare added to overcome the disadvantage of the large friction betweensilicone rubber and glass. However, the addition of glass spheres wouldcause the difficulty in mixing and the difficulty of bonding glassspheres and silicone rubber. Besides, the problems whether glass sphereswould crack and cause safety incipient faults of the screen wiper are tobe solved.

WO 3/050191 discloses an anti-friction screen wiper, wherein the rawmaterial used includes ethyl vinylsiloxane polymer, fillers andanti-friction additives such as PTFE (polytetrafluoroethylene), etc.Although the addition of a certain amount of PTFE can lower thefriction, the plasticity of the material is enhanced at the same time,leading to the difficulty or even incapability in extruding and molding.

SUMMARY OF THE INVENTION

The inventors of the present invention have surprisingly discovered thata self-lubricating organic-silicone rubber material can be obtained bymixing organic-silicone rubber and a self-lubricating solid additive,and adding other auxiliary components at the same time. Such a siliconerubber material possesses an excellent self-lubricating property andconvenience in preparation, and can overcome the above defects existingin the prior art, so it has a wide foreground of applications.

One of the objectives of the present invention is to provide anorganic-silicone rubber material with the self-lubricating property.

Another objective of the present invention is to provide a process forpreparing said silicone rubber material.

A further projective of the present invention is to provide a productmade from the self-lubricating, organic-silicone rubber material of thepresent invention.

The present invention provides a self-lubricating organic-siliconerubber material, which comprises an organic-silicone rubber, aself-lubricating additive, filler and a vulcanizing agent, andoptionally, a release agent and a pigment.

The present invention also provides a process for preparing theself-lubricating organic-silicone rubber material, which comprises thefollowing steps: mixing an organic silicone rubber, a self-lubricatingadditive and filler, then adding a vulcanizing agent and optionally, arelease agent and a pigment to the obtained mixture.

DETAILED DESCRIPTION

The present invention will be described below in detail.

Organic-Silicone Rubber:

There is no special limitation to the organic-silicone rubber suitablefor the present invention and the organic-silicone rubbersconventionally used in the art. All can be used in the presentinvention, such as dimethicone polymer, methyl vinyl siloxane polymer,methyl styryl siloxane polymer, methyl styryl siloxane polymer, andmethyl trifluoropropyl siloxane polymer, etc. The above organic-siliconerubbers can be used alone, or as a mixture of two or more of them. Thepreferably used organic-silicone rubbers are those whose end group ismethyl, vinyl or combination thereof, such as:

Me₃SiO(Me₂SiO)_(n)SiMe₃;

Me₃SiO(Me₂SiO)_(n)(MeViSiO)_(m)SiMe₂R;

RMe₂SiO(Me₂SiO)_(n)(MePhSiO)_(l)(MeViSiO)_(m)SiMe₃;

Me₃SiO[Me(CF₃CH₂CH₂)SiO]_(n)SiMe₃,

Where Me represents methyl; n, m and l are integers greater than 0,which may be the same or different; R represents methyl or vinyl; Vi isvinyl.

The content of the organic-silicone rubber in the self-lubricatingorganic-silicone rubber material of the present invention may be 10-70%by weight, preferably 30-60% based on the total weight of theself-lubricating organic-silicone-rubber material.

Self-Lubricating Additive:

Self-lubricating additives are-those which impart the organic-siliconerubber with the self-lubricating property and thereby lower the frictionbetween the silicone rubber and glass and/or those which preventjumpiness and noise from accruing when the organic-silo cone rubber andglass are contacted and slided.

The self-lubricating additive suitable for the present invention may beselected from the group consisting of graphite, fluorine-containingcompounds, boron nitride, dimethicone, methyl hydrogen-containingsilicone oil, ethyl silicone oil, vinyl silicone oil, stearates, andmixtures thereof. the preferred self-lubricating additive is selectedfrom the group consisting of fluorizated graphite, teflon powder, methylhydrogen-containing silicone oil, vinyl silicone oil, zinc stearate,barium stearate, and mixtures thereof.

There is no special limitation to the content of the self-lubricatingadditive as long as the content can impart the material with the desiredself-lubricating property. In general, the content of theself-lubricating additive may be 2-30% by weight, preferably 3-20% ofthe total weight of the self-lubricating organic-silicone rubbermaterial.

Filler:

The well-known fillers which can improve the mechanical property of theorganic silicone rubber are all suitable for the present invention, suchas those well-known strengthening fillers. The preferred filler of thepresent invention includes synthesized silica micro powder, naturalquartz powder, kieselgur, and kaolin, etc.

The content of the filler may be 20-70%, preferably 30-6O0% of the totalweight of the self-lubricating organic-silicone rubber material.

Vulcanizing Agent:

All the well-known vulcanizing agents can be used in the presentinvention. The preferred vulcanizing agent includes various organicperoxides. The present invention prefers the use of benzoyl peroxide.

In general, a vulcanizing agent accounting for 1-2% of the total weightof the self-lubricating organic-silicone rubber material is needed.

Release Agent:

Release agents well-known in the art are all usable in the presentinvention. The content of the release agent can be determined by theskilled in the art according to their common knowledge.

Pigment:

Various pigments available in the market and suitable for the additionto organic silicone rubber can be added according to the demand for thecolor. The content can be determined by the skilled in the art accordingto their common knowledge and the demand for the color.

Preparation:

The self-lubricating organic-silicone rubber of the present inventioncan be prepared by the following process:

-   -   (1) adding the organic-silicone rubber, self-lubricating        additive and filler to an internal mixer and mixing therein;    -   (2) adding the vulcanizing agent and optionally, release agent        and pigment to the mixture contained in step (1);    -   (3) letting the mixture obtained in step (2) stand still; and    -   (4) optionally, making the product obtained in step (3) into the        required product.

In particular, the organic-silicone rubber, self-lubricating additiveand filler are added to internal mixer and mixed well, and the mixturestands still for 1-24 hours to fully disperse the self-lubricatingadditive into the filler. Then the thus obtained mixture is added toopen mixer, and the vulcanizing agent and optionally, the release agentand pigment are added and mixed. The thus obtained mixture stands stillfor more than 12 hours to uniformly disperse the vulcanizing agent.

The self-lubricating organic-silicone rubber material of the presentinvention can be made into the required product by conventional moldingand extruding methods.

The self-lubricating organic-silicone rubber material of the presentinvention can be used in various places where self-lubricating materialsare needed such as various glass cleaning appliances andself-lubricating tubes like peristaltic pump tubes, etc.

The self-lubricating organic-silicone rubber material of the presentinvention is especially suited to the screen wiper of vehicles. Thescreen wiper of vehicles made from the self-lubricating organic-siliconerubber of the present invention possesses an excellent self-lubricatingproperty, water-wiping performance, and abilities to clean the surfaceof glass well without generating water trace and prevent the screenwiper from jumping and generating noise. Besides, the thus preparedscreen wiper possesses excellent resistance to heat, violet ray, andozone, and thereby possesses an ideal stability, weather-resistance, andaging-resistance, no longer being short-term consumable products whilethe screen wiper possesses excellent self-lubricating and cleaningproperties. The comparison between an ordinary screen wiper and thescreen wiper of the present invention is listed in the following table:

Ordinary screen Screen wiper of the present wiper invention Weatherresistance Bad Good Water-wiping Fairish Self-lubricating water-wipingperformance Jumping property Fairish None Color Black Adjustable

General Preparation Procedure:

A certain amount of organic-silicone rubber, self-lubricating additiveand filler are added to an internal mixer and uniformly mixed, and themixture stands still for 24-hours to fully disperse the self-lubricatingadditive in the filler. Then the obtained mixture is added to an openmixer, and an adequate amount of vulcanizing agent, release agent, andpigment are added and fully mixed. The obtained mixture stands still formore than 24 hours.

The examples listed in the following table were operated according tothe above general procedure:

Example 1 Example 2 Example 3 Organic- QT-040U QT-060U QT-080U silicone800 g 850 g 850 g rubber Self- MD-188A MD-188A MD-188A lubricating 150 g 70 g 300 g agent Filler PD-30 Quartz 30μ 10μ Kieselgur PD-30 300 gPowder quartz quartz 520 g 520 g 300 g powder powder 585 g 585 gVulcanizing Benzoly peroxide Benzoly peroxide Benzoly peroxide agent  20g  36 g  40 g Release QA-850B QA-850B QA-850B agent  1.5 g  2.1 g  2.5 gPigment Black — Blue  1.5 g  2.5 g QT-040U: commercially available fromthe producer: British Condor Science-Technology Co. Ltd.; QT-060U:commercially available from the producer: British CondorScience-Technology Co. Ltd.; QT-O80U: commercially available from theproducer: British Condor Science-Technology Co. Ltd.; MD-188A: a mixtureof a fluorine-containing compound and stearate commercially availablefrom the producer: Taiwan Xinzhong Co. Ltd.; QT-O850B: commerciallyavailable from the producer: British Condor Science Technology Co. Ltd.;PD-30: 30 micro calcined kaolin, commercially available from theproducer: Liyang Electronic Science-Technology Co. Ltd.

Test on the Self-Lubricating Effect:

The self-lubricating organic-silicone rubber materials prepared in theabove examples are made into products by molding. After standing stilland insolating for 1-2 weeks, there were still wiped water and greaseslightly appearing on the surface of the products with a lubricatingfeeling.

Conclusion:

The above examples are only used to illustrate but not limit the presentinvention. One skilled in the art can make any variations andmodifications as long as these variations and modifications do notdeviate from the sprits of the present invention and they are stillwithin the scope of the present invention.

1. A self-lubricating organic-silicone rubber material comprising: a.organic-silicone rubber; b. self-lubricating additive; c. filler; d.vulcanizing agent; and e. optionally, release agent and pigment.
 2. Thematerial according to claim 1, wherein said self-lubricating additive isselected from the group consisting of graphite, fluorine-containingcompounds, boron nitride, dimethicone oil, methyl hydrogen-containingsilicone oil, ethyl silicone oil, vinyl silicone oil, stearates, andmixtures thereof.
 3. The material according to claim 1, wherein saidself-lubricating additive is selected from the group consisting offluorizated graphite, teflon powder, methyl hydrogen-containing siliconeoil, vinyl silicone oil, zinc stearate, barium stearate, and mixturesthereof.
 4. The material according to claim 1, wherein saidself-lubricating additive is MD-188A.
 5. The material according toclaims 1, wherein said filler is selected from quartz powder, kaolin andmixtures thereof.
 6. The material according to claim 1, wherein saidfiller is kaolin.
 7. The material according to claim 1, wherein saidvulcanizing agent is benzoyl peroxide.
 8. The material according toclaim 1, wherein said organic-silicone rubber accounts for 10-70% byweight of the total weight of said self-lubricating organic-siliconerubber material.
 9. The material according to claim 1, wherein saidself-lubricating additive accounts for 2-30% by weight of the totalweight of said self-lubricating organic-silicone rubber material. 10.The material according to claim 1, wherein said self-lubricatingadditive accounts for 3-20% by weight of the total weight of saidself-lubricating organic-silicone rubber material.
 11. The materialaccording to claim 1, wherein said filler accounts for 20-70% by weightof the total weight of said self-lubricating organic-silicone rubbermaterial.
 12. A process for preparing a self-lubricatingorganic-silicone rubber material comprising the steps of: a. mixing (1)an organic-silicone rubber, (2) a self-lubricating additive and (3) afiller, b. adding a vulcanizing agent thereby forming a mixture, and c.optionally adding a release agent and a pigment to the mixture.
 13. Theprocess according to claim 12, further comprising the following stepsof: a. adding the organic-silicone rubber, the self-lubricating additiveand the filler to a internal mixer; b. mixing therein thereby forming afirst mixture; c. letting the first mixture stand still for 1-24 hours;d. adding the first mixture to an open mixer, to which the vulcanizingagent, release agent and pigment are added, thereby forming a secondmixture; and e. letting the second mixture stand still for 12 or morethan 12 hours.
 14. A screen wiper made from a self-lubricatingorganic-silicone rubber material comprising: a. organic-silicone rubber;b. self-lubricating additive; c. filler; d. vulcanizing agent; and e.optionally, release agent and pigment.
 15. The screen wiper according toclaim 14, wherein said self-lubricating additive is selected from thegroup consisting of graphite, fluorine-containing compounds, boronnitride, dimethicone oil, methyl hydrogen-containing silicone oil, ethylsilicone oil, vinyl silicone oil, stearates, and mixtures thereof. 16.The screen wiper according to claim 14, wherein said self-lubricatingadditive is selected from the group consisting of fluorizated graphite,teflon powder, methyl hydrogen-containing silicone oil, vinyl siliconeoil, zinc stearate, barium stearate, and mixtures thereof.
 17. Thescreen wiper according to claim 14, wherein said self-lubricatingadditive is MD-188A.
 18. The screen wiper according to claims 14,wherein said filler is selected from quartz powder, kaolin and mixturesthereof.
 19. The screen wiper according to claim 14, wherein said filleris kaolin.
 20. The screen wiper according to claim 14, wherein saidvulcanizing agent is benzoyl peroxide.
 21. The screen wiper according toclaim 14, wherein said organic-silicone rubber accounts for 10-70% byweight of the total weight of said self-lubricating organic-siliconerubber material.
 22. The screen wiper according to claim 14, whereinsaid self-lubricating additive accounts for 2-30% by weight of the totalweight of said self-lubricating organic-silicone rubber material. 23.The screen wiper according to claim 14, wherein said self-lubricatingadditive accounts for 3-20% by weight of the total weight of saidself-lubricating organic-silicone rubber material.
 24. The screen wiperaccording to claim 14, wherein said filler accounts for 20-70% by weightof the total weight of said self-lubricating organic-silicone rubbermaterial.